ENVIRONMENTAL TOBACCO-SMOKE - IS IT REALLY A CARCINOGEN

This review challenges a recent conclusion of Law and Hackshaw [Britis h Medical Bulletin 1996, 52, 22-34] that it is ''beyond reasonable dou bt that a causal relationship exists between environmental tobacco smo ke (ETS) exposure and lung cancer''. The main reasons for our objectio ns are as follows: The epidemiological studies have been shown by us a nd many others to be seriously flawed. The use of a single cotinine as say as a measure of longterm ETS exposure is almost certainly not vali d. There is much scientific evidence to support the existence of thres holds for genotoxic carcinogens. The claim that ETS causes lung cancer , therefore, appears to be more a statement of belief, rather than a c onclusion based on strict scientific objectivity.